1. Field of the Invention
This invention relates to photomechanical processes, specifically to such processes which are used to alter the hue, tonality and definition of a photographic image.
2. Description of Prior Art
A commercial market exists for multicolor photographic images that appear antiquated in appearance. Such antiquated images exhibit characteristics such as increased or darkened tonality, loss of sharpness, loss of hue, and the presence of a general color cast (usually amber or sepia). Thus, the term "antiquated" in this patent refers to any positive color photographic image which exhibits all of the above visual characteristics, or resembles color photographic images made prior to 1936. Furthermore, the term "antiquation" may also refer to the process of achieving an antiquated image.
One of the original methods used to achieve antiquated color is the hand tinting of black and white photographs. This practice is still done today. This method's primary advantage is that it allows the colorist to enhance a given feature in an image by highlighting the desired feature with an attractive color while de-emphasizing the other areas with a more muted color. However, hand-tinting method has notable limitations. As a practical measure, it is limited to negative black-and-white film printed on fiber-based, or non-glossy, or absorbent paper, In addition, the colorist is generally limited to soft pastel hues. More importantly, hand-tinting is time consuming and thus costly. As a consequence, customers are often required to select a black and white image for colorization without knowing how the result will appear.
Sepia toning and sepia filters are sometimes used to achieve antiquated multicolor images. This practice is done either by placing a transparent, sepia-colored filter between the film and the light source or by using toning solution immediately after development. While these methods are both quick and inexpensive, they produce multicolor images that only vaguely resemble antiquated images as previously defined. At best, sepia colorization creates a vivid contemporary color picture with an amber cast.
Antiquated multicolor images may also be created by using multiple gum or other color separation processes. These methods are original but very cumbersome because they require multiple exposures of an image before it can be transformed into a multicolor picture.
Perhaps the most practical method for producing color antiquated photographs was the Autochrome method developed by the Lumiere brothers. Their method was successfully marketed from 1907 to 1936. The Autochrome method utilized the concept of the multicolor screen. In general, the color screen consists of a screen pattern that is formed by a plurality of light-filtering elements.
A conventional three-color screen has a set of primary red colored filter elements, a set of primary blue colored filter elements, and a set of primary green colored filter elements. Alternatively, the color screen may also employ yellow, cyan, magenta, or other related color elements. One preferred arrangement is of a mosaic type; that is, a less than strictly geometric arrangement with regard to element size shape, and/or color placement with each element measuring between one to three hundred microns in diameter. Thus the individual screen elements are not easily distinguished by the unaided eye.
Several methods may be used to produce the multicolor screen as described above. Basically, the methods of color screen production fall into three main categories: mechanical methods, photochemical processes, and electronic transfer methods. In the mechanical methods, screen elements are formed largely without chemical reactions. In the photochemical processes, multicolor screens are produced largely as a function of exposure and development. Finally, in the electronic transfer methods, visual characteristics are converted into digital or analog signals which are then translated into a variety of visual media.
With the Lumiere method, a dust of red, green, and blue colored starch particles was allowed to settle onto the tacky surface of a sheet of glass. Then the particles were flattened out into tiny screen elements measuring about 0.015 millimeters in diameter. The resulting screen was then covered with a panchromatically sensitized black and white positive emulsion. The exposed and developed plate would yield a reasonably faithful multicolor image upon projection. While a practical method for its time, Autochrome suffered two primary drawbacks. First, the color screen absorbed about seventy-five percent of the light, resulting in the necessity for lengthy exposures. Secondly, the multicolor screen had to remain in register with its emulsion coating, thus requiring a new screen for each image exposed.
Since Autochrome, many films have been developed to employ multicolor screens with their emulsion systems, notably: U.S. Pat. No. 3,519,423 Sharp, Jul. 7, 1970 method of making multicolor screens, U.S. Pat. No. 3,925,082 Fielding et al, Dec. 9, 1975 multicolor screen containing hydrophilic colloid . . . , U.S. Pat. No. 4,362,806 Dec. 7, 1982 Whitmore Imaging with nonplaner support elements: and U.S. Pat. No. 4,463,074 Jul. 31, 1984 Gilmour/Blazey et al, elements containing ordered wall arrays.
The latter patent of Gilmour/Blazey is an improvement of the Whitmore patent. The Gilmour/Blazey patent employs both mechanical and photomechanical methods to create microscopic cavities known as micro cells or reaction micro vessels. These cavities may then be filled with a variety of imaging and or coloring components by using doctor blade coating, solvent casting, or other conventional coating techniques.
Difficulties arise when comparing Gilmour/Blazey, with the present invention. Some of the stated objectives of Whitmore, the predecessor to Gilmour/Blazey, were the following: enhanced contrast, correct reading color, improved definition, enhanced film speed (without graininess), and the reduction of lateral image spreading or halation. Subsequent improvements by Gilmour/Blazey were in accord with these objectives. In contrast, the primary objectives of the present invention are the following: the alteration of the characteristics of an image so as to affect darkened tonality, loss of sharpness or definition, loss or muting of color, and the presence of a general color cast (usually amber or sepia). These characteristics, when taken collectively, cause an image to be perceived as antiquated in appearance as described above.
The former patent, Gilmour/Blazey, has the following limitations:
(a) The color screen produced is physically attached to a light sensitive emulsion, or the screen is otherwise integrated with the image. This attachment forms elements of a photographic emulsion, thereby causing the production of a separate color screen for each exposure formed. PA1 (b) In order to utilize the former patent, the photographer must expend a separate color screen for each image recorded. PA1 (c) Because the multicolor screen is performed in the initial unexposed film, the photographer who uses rolled film may not alternate or otherwise change imaging characteristics during recording without changing film. For example, when using a ten exposure roll, the photographer may not record the first five exposures without the multicolor screen and the last five exposures with it. PA1 (d) Production of the multicolor screens in the Gilmour/Blazey patent involves multiple steps and industrial techniques, therefore requiring substantial equipment, energy, and capital investment. PA1 (e) The size ratio of the individual colored elements to the film image is fixed in production. This ratio limits the enlargement of an image to a given size beyond which the individual areas of the multicolor screen become readily visible to the unaided eye. PA1 (a) To provide a means by which multicolor photographic images that are generally described as old fashioned or antiquated in appearance may be produced. PA1 (b) To provide a means by which antiquation may be affected quickly and inexpensively. PA1 (c) To provide a means by which the photographer may affect antiquation on selected exposures of rolled film and omit it on others without changing the film. PA1 (d) To provide a means by which an indefinite number of photographic images may be antiquated by using a single multicolor screen configuration. PA1 (e) To provide a means by which antiquation may be affected without placing the multicolor screen in register with the recording film. PA1 (f) To provide a means by which antiquation may be affected from images recorded on any color film stock, regardless of format, film speed, or negative or reversal category. PA1 (g) To provide a means by which the size relationship between the individual areas of the multicolor screen and the recorded image may be conveniently varied so that an enlargement of any size may be obtained without rendering individual areas clearly visible to the unaided eye.